---
title: MCP Registry Aggregators
sidebarTitle: Registry Aggregators
---

Aggregators are downstream consumers of the MCP Registry that provide additional value. For example, a server marketplace that provides user ratings and security scanning.

The MCP Registry provides an unauthenticated read-only REST API that aggregators can use to populate their data stores. Aggregators are expected to scrape data on a regular but infrequent basis (e.g., once per hour), and persist the data in their own data store. The MCP Registry **does not provide uptime or data durability guarantees**.

## Consuming the MCP Registry REST API

The base URL for the MCP Registry REST API is `https://registry.modelcontextprotocol.io`. It supports the following endpoints:

- [`GET /v0.1/servers`](https://registry.modelcontextprotocol.io/docs#/operations/list-servers-v0.1) — List all servers.
- [`GET /v0.1/servers/{serverName}/versions`](https://registry.modelcontextprotocol.io/docs#/operations/get-server-versions-v0.1) — List all versions of a server.
- [`GET /v0.1/servers/{serverName}/versions/{version}`](https://registry.modelcontextprotocol.io/docs#/operations/get-server-version-v0.1) — Get a specific version of a server. Use the special version `latest` to get the latest version of the server.

<Warning>

URL path parameters such as `serverName` and `version` **must** be URL-encoded. For example, `io.modelcontextprotocol/everything` must be encoded as `io.modelcontextprotocol%2Feverything`.

</Warning>

Aggregators will most likely scrape the `GET /v0.1/servers` endpoint.

### Pagination

The `GET /v0.1/servers` endpoint supports cursor-based pagination.

For example, the first page can be fetched using a `limit` query parameter:

```bash
curl "https://registry.modelcontextprotocol.io/v0.1/servers?limit=100"
```

```jsonc Output highlight={5}
{
  "servers": [
    /* ... */
  ],
  "metadata": {
    "count": 100,
    "nextCursor": "com.example/my-server:1.0.0",
  },
}
```

Then subsequent pages can be fetched by passing the `nextCursor` value as the `cursor` query parameter:

```bash
curl "https://registry.modelcontextprotocol.io/v0.1/servers?limit=100&cursor=com.example/my-server:1.0.0"
```

### Filtering Since

The `GET /v0.1/servers` endpoint supports filtering servers that have been updated since a given timestamp.

For example, servers that have been updated since 2025-10-23 can be fetched using an `updated_since` query parameter in [RFC 3339](https://datatracker.ietf.org/doc/html/rfc3339) date-time format:

```bash
curl "https://registry.modelcontextprotocol.io/v0.1/servers?updated_since=2025-10-23T00:00:00.000Z"
```

## Server Status

Server metadata is generally immutable, except for the `status` field which may be updated to, e.g., `"deprecated"` or `"deleted"`. We recommend that aggregators keep their copy of each server's `status` up to date.

The `"deleted"` status typically indicates that a server has violated our permissive [moderation policy](./moderation-policy.mdx), suggesting the server might be spam, malware, or illegal. Aggregators may prefer to remove these servers from their index.

## Acting as a Subregistry

A subregistry is an aggregator that also implements the [OpenAPI spec](https://github.com/modelcontextprotocol/registry/blob/main/docs/reference/api/openapi.yaml) defined by the MCP Registry. This allows clients, such as MCP host applications, to consume server metadata via a standardized interface.

The subregistry OpenAPI spec allows subregistries to inject custom metadata via the `_meta` field. For example, a subregistry could inject user ratings, download counts, and security scan results:

```json server.json highlight={17-26}
{
  "$schema": "https://static.modelcontextprotocol.io/schemas/2025-10-17/server.schema.json",
  "name": "io.github.username/email-integration-mcp",
  "title": "Email Integration",
  "description": "Send emails and manage email accounts",
  "version": "1.0.0",
  "packages": [
    {
      "registryType": "npm",
      "identifier": "@username/email-integration-mcp",
      "version": "1.0.0",
      "transport": {
        "type": "stdio"
      }
    }
  ],
  "_meta": {
    "com.example.subregistry/custom": {
      "user_rating": 4.5,
      "download_count": 12345,
      "security_scan": {
        "last_scanned": "2025-10-23T12:00:00Z",
        "vulnerabilities_found": 0
      }
    }
  }
}
```

We recommend that custom metadata be put under a key that reflects the subregistry (e.g., `"com.example.subregistry/custom"` in the above example).
